Was: Air won't build... Now: Air Dryer fitment

Topic: Was: Air won't build... Now: Air Dryer fitment (Read 2693 times) previous topic - next topic

Was: Air won't build... Now: Air Dryer fitment

July 29, 2014, 02:42:44 pm

We were cruising along all systems go, all of a sudden level system warning light comes on and travel light is out. Air pressure dropped to 90 in front and 70 in back. So pulled off and stopped at the first margin wide enough to get off the highway. I have a Bendix D2 governor with me. I need to find where in the engine compartment it is and how to tell if that is the problem... And I need to find out ASAP! Any trouble shooting suggestions would be welcome. I have the air schematic handy, I don't see the governor labeled on it, though I think I can tell which symbol is it from the proximity to the compressor. Going to pop the bed and see if I can spot it now.
Don

Re: Air won't build past 40psi, stuck by roadside

Reply #1 – July 29, 2014, 02:53:23 pm

It shoukd be to the right of the engine as you face it. It has a black cover on it and under the AC compressor. You can take off the black cover and turn the screw all the way one direction then back the other way. It should free the diaphragm and lit you build air. I think you turn it counter clockwise but it has been four years since I had to do it. Then open it up again and see if you build air. It should get you off the road where you can change it out.

Re: Air won't build past 40psi, stuck by roadside

Reply #2 – July 29, 2014, 02:56:44 pm

Hi Don,
On our 1997 U320 the governor is just behind the air conditioner compressor. Not to hard to reach from the back/outside. It may be the same location for you. Best of luck.
Raymond

Re: Air won't build past 40psi, stuck by roadside

Reply #3 – July 29, 2014, 03:08:21 pm

If that doesn't fix it then go to air purge valve on the bottom side of air drier.

Re: Air won't build past 40psi, stuck by roadside

Reply #4 – July 29, 2014, 03:09:23 pm

The gov will probably be the culprit... my suggestion of purge valve is next.

Re: Air won't build past 40psi, stuck by roadside

Reply #5 – July 29, 2014, 03:22:30 pm

Something similar happened to me last year only I was parked and could not release the brake. It was the air dryer filter, it had come loose about a half a turn. Re tightened and air pressure returned. Cost me $80 for that lesson. This has happened two more times. Per the advise of an old mechanic friend put a clamp and a small spring on it to keep it tight.

Re: Air won't build past 40psi, stuck by roadside

Reply #6 – July 29, 2014, 03:23:14 pm

With new D2 in hand look on right rear frame for the old unit if it is where mine is on my 1998. Was in plan sight on the frame rail, curb side. On my 1993 it was mounted on engine block almost impossible to see, curb side, from inside with bed up. I found it easier to replace with the D2 off the block, when trying to get the tubing nuts to make up again.

Re: Air won't build past 40psi, stuck by roadside

Reply #7 – July 29, 2014, 04:35:07 pm

Don,
Here is where the governor is located on our 99 U270. Mark

Re: Air won't build past 40psi, stuck by roadside

Reply #8 – July 29, 2014, 04:51:54 pm

Quote from: MAZ – July 29, 2014, 04:35:07 pm

Don,
Here is where the governor is located on our 99 U270. Mark

Is that the original location of your Cummins air filter or did you relocate it there? I like that location far more than where mine is.

Re: Air won't build past 40psi, stuck by roadside

Reply #9 – July 29, 2014, 04:56:47 pm

Quote from: rsihnhold – July 29, 2014, 04:51:54 pm

Is that the original location of your Cummins air filter or did you relocate it there? I like that location far more than where mine is.

That is the factory location.

Mark

Re: Air won't build past 40psi, stuck by roadside

Reply #10 – July 29, 2014, 05:26:11 pm

Update... Changed out the air Gov., no change in symptoms. Still won't build pas t 30 psi or so. The air dryer has what I think is a purge valve that is continuously dumping air while running. The exhaust port on the new Gov is also outputting air continuously but I think it normally does that until cut out. Should the bottom of the air dryer have some kind of hood or muffler? It was extremely dirty there and also has what looks like an adjustment screw. I don't think it should be dumping air like that when it isn't up to pressure... Thoughts? Does anyone have the part number of the dryer purge valve for a 99' ISC.
Don

Re: Air won't build past 40psi, stuck by roadside

Reply #11 – July 29, 2014, 05:32:55 pm

depending on how close you are to a truck or hardware store, you can bypass the airdryer altogether with pipe fittings and a 1/4 plug. Disconnect the 2 large hoses at the bottom of the dryer and get pipe thread beveled connectors to join the 2 together. Then find the 1/4" hose that comes from the governor to the side of the dryer and screw the plug into that and you can run at 110 lbs forever. Happened to me in the middle of the desert.

Re: Air won't build past 40psi, stuck by roadside

Reply #12 – July 29, 2014, 05:35:07 pm

Quote from: acousticart – July 29, 2014, 05:26:11 pm

The exhaust port on the new Gov is also outputting air continuously but I think it normally does that until cut out. Should the bottom of the air dryer have some kind of hood or muffler? It was extremely dirty there and also has what looks like an adjustment screw. I don't think it should be dumping air like that when it isn't up to pressure... Thoughts? Does anyone have the part number of the dryer purge valve for a 99' ISC.

Don,

Haldex Pure Air Plus is the air dryer. Service kits with part numbers are on this page:

http://epi.hbsna.com/products/dept.asp?msi=0&sid=974DA552B9D44D01BBD190038AAA6798&dept_id=2581&parent_id=0

Large truck parts/service place should have service kits. Some NAPAs may have them in stock as well.

Bit of a warning, IIRC that purge valve is notorious for snapping off in the dryer when you try to remove it.

Re: Air won't build past 40psi, stuck by roadside

Reply #13 – July 29, 2014, 05:58:23 pm

Don,
I think these may help -- all of our OEM installed dryers are alike, so if yours hasn't been redesigned.......
Sounds to me as though the Governor is unloading but the purge valve is stuck or only partially shifting. The compressor can't build air with the purge valve stuck partially open.
As Twig already suggested, I would temporarily bypass the air dryer until I got somewhere that I could put in a remanufactured air dryer (easiest) or rebuild what you have with a new purge valve (more difficult).
Neal

Re: Air won't build past 40psi, stuck by roadside

Reply #14 – July 29, 2014, 06:19:53 pm

I know you have a Haldex air dryer, but for the benefit of readers who have a Bendix air dryer, there are four little bolts on the bottom of the air dryer around the purge valve allowing you to change out the purge valve on the side of the road in a matter of minutes if you have one with you... which you probably should cuz they're inexpensive, small, and lightweight... but even if you don't have a new purge valve with you take out the old one, clean it, and put it back in to see if that fixes it.

Re: Air won't build past 40psi, stuck by roadside

Reply #15 – July 29, 2014, 06:46:28 pm

Okay, useful suggestions abound! Thanks one and all! I may have the parts to bypass the dryer with me, but there are several hoses connected to the dryer and a 1/4" plastic air line, which I believe is the one that Twig said needs to be plugged. That I have done. The outlet hose on the bottom of the dryer assy appears to have 3/4" female pipe thread (I haven't removed it yet) and there is one othe slightly smaller outside diameter hose that is connected up on the side. Are these the two hoses that need to be joined to bypass the dryer? I happen to have a short 3/4" pipe nipple with me if that is the correct size. I also have a 1/2" nipple as well, but pretty sure it isn't that. If this works out, I will by a rebuilt unit in Calgary and take the old one to rebuild back home.
Don

Re: Air won't build past 40psi, stuck by roadside

Reply #16 – July 29, 2014, 07:19:45 pm

I have tried to attach a picture off the fitting I used.

Re: Air won't build past 40psi, stuck by roadside

Reply #17 – July 29, 2014, 07:33:48 pm

Don,
On mine I disconnected the two big lines at the bottom of the dryer then connected them with the above fitting.
Big line from the compressor and big line from the dryer to the wet tank .
I disconnected the 1/4 inch line that went it the wet tank.
All info I got from Twig while sitting on the side of the road.

Re: Air won't build past 40psi, stuck by roadside

Reply #18 – July 29, 2014, 07:37:04 pm

Don, I know there have been many suggestions here but my 2 cents is that if you can get a service kit for it close to were you are just take it off and rebuild or just do the purge. It really is easy to do even in place. You have masterd many tough issues so this one to you is a 1 out of 10. I have done this rebuild now 5 times (total service) and wish all things are that easy.
JohnH

Re: Air won't build past 40psi, stuck by roadside

Reply #19 – July 29, 2014, 09:10:53 pm

Ty's went in the toad to try and find a fitting. Nearest town is 13 miles from here and not very large. I guess the in and out hoses are the ones with the ¾" threads are the two to join. Still not sure about the ¼" line to plug. The one that goes to the governor is braided and uses a similar tapered fitting as the large hoses only smaller. The one I have a plug fore is a ¼" plastic line like the step air cylinder uses, a compression ring fitting. We only have slow internet on our phones at the moment. I will try to attach a picture of the bottom of the dryer with the two large hoses removed. Can anyone confirm that the two hoses that attach to the areas where a hose has obliviously been removed are the correct ones to join and that the plastic line (still in place here) is the one two plug?
Thanks, Don
Edit: naturally, posting picture from my phone ends up upside down

Re: Air won't build past 40psi, stuck by roadside

Reply #20 – July 29, 2014, 09:17:46 pm

Quote from: acousticart – July 29, 2014, 09:10:53 pm

Edit: naturally, posting picture from my phone ends up upside down

Don't worry about it - we can see what you're asking about (wish I had the answer, but I'm sure someone will chime in soon).

Where are you guys currently located? Maybe a Fofum familiar with the area can offer parts vendor suggestions?

Re: Air won't build past 40psi, stuck by roadside

Reply #21 – July 29, 2014, 09:32:47 pm

Bless you Michelle! We are 49 miles south of Calgary in Alberta, Canada on north bound HWY 2 (just north of a town called Nanton).
Don

Re: Air won't build past 40psi, stuck by roadside

Reply #22 – July 29, 2014, 11:14:10 pm

Don, been looking on google earth and there are a few diesel shops around High River but most of course in SE Calgary. Nanton seems pretty big enough for a shop. Find the local cop shop RCMP and ask them to locate one for you.
JohnH

Re: Air won't build past 40psi, stuck by roadside

Reply #23 – July 29, 2014, 11:25:35 pm

Don,
I've used Calgary Diesel Services in the past; they are in south Calgary and good to work with. Their number is (403) 262-5750 (ask for Peter or Rod). If they have what you need (they may also have a new/replacement dryer on hand), I could pick it up for you and bring it out first thing in the morning.
Grant

Re: Air won't build past 40psi, stuck by roadside

Reply #24 – July 30, 2014, 12:35:29 am

Don,
Attached find some notes on your photograph. My Control Port from the governor is nearly opposite the inlet port. There is a label "Control" cast right into the dryer bottom casting. Yours looks a bit different. But there is only one line, with 1/8" NPT end fittings, that goes directly from the governor to the dryer. That's the one you need to plug -- at either end.
After bypassing the dryer, on engine start, watch your gauges carefully to make sure that the compressor is still being controlled by the governor. Be ready to shut down if pressure isn't being properly controlled.
Good luck and best wishes.
Neal

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